Manufacture of screen-plates for paper-machines



(No Model.)

J. M. SHEW. Manufacture of Screen Plates for Paper Machines.

No. 239,276. Patented March 22,1881.

Q jlnvaZ N-PEYERS. PIIQTO-LI'IHDGRAPHER. WASHINGTON. n. c.

UNITED STATES PATENT OFFICE.

JAMES M. SHEW, OF PAPER MILLS, ASSIGNOB OF ONE-HALF TO GEORGE W. S. HOFFMAN, OF BALTIMORE, MARYLAND.

MANUFACTURE OF SCREEN-PLATES FOR PAPER-MACHINES.

SPECIFICATION forming part of Letters Patent No. 239,276, dated March 22, 1881.

Application filed February 17, 1881. (No model.)

To all whom it may concern:

Be it known that I, JAMES M. SHEW, of the village of Paper Mills, county of Baltimore, and State of Maryland, have invented a new and useful Improvement in the Manufacture of Screen-Plates for Paper-Machines, of which the tbllowing is a full, clear, and exact description, reference being had to the accompanying drawings, making a part of this speci- 1O fication, in which- Figure l is a perspective view of a screenplate with my improvement attached. Fig. 2 is a cross-section on the line 00 w of Fig. 1.

Myinvention relates to machines for the manufacture of paper; and it consists in grooving the top of the screen-plate between the slits to retard or prevent the edges of the slit from becoming enlarged by the cutting action of the grit in the pulp.

To enable others skilled in the art to make and use my invention, 1 will proceed to describe the exact manner in which I have carried it out.

1n the ordinary paper-machine the finished paper-pulp, or stufi' to be felted into paper, is

' passed out of the stutt chest into a box containing a set of perforated or slitted plates,

technically called the screen-plates. These screen-plates are about a quarter of an inch 0 thick, usually made of metal, but sometimes of hard rubber or other material, and are made into a screen by perforating or slitting them with many very narrow slits or slots. As usually constructed, the face of these plates is 3 5 perfectly smooth and flat, the edges of the slits being rectangular, and on the same plane as the general level of the upper surface of the plate. When the paper-pulp comes in contact with. this screen-plate, which is subjected to a 0 constant vibrating motion, a portion of the sand or dirt will pass through the slits, while other portions remain on the upper surface of the screen. These particles of sand, grit, or

the screen-plate.

dirt, if allowed to remain upon the surface of the screen-plate, which is kept ina state of vibratory motion, gradually abrade or cut away the edges of the slits,therebyincreasing the width of the same and rendering the plate unfit to properly perform its office.

' My invention consists in a device for pre- 0 venting or retarding the enlargement of the slits by the cutting action of grit, 850., as above described. This I effect by grooving out the usual plain surface of the screen-plates between the slits to the depth of an eighth'ot' an inch, more or less. The effect of this grooving is to cause the particles of dirt, &c., that do not pass through the slits to fall away from the edges into the grooves and below the level of the slits, and thus prevent the cutting action and the enlargement of the slits of the screen-plates. The form and size of the groove are immaterial within certain limits; but I prefer to make a curved groove, the end ofwhi'ch terminates within about an inch of the edgeof 6 The sand or grit collects in these grooved receptacles,from which it can be readily removed.

In the drawings, A represents ascreen-plate provided with the slits a, and having the grooves or depression B in the upper face of the plate between the slits. These grooves may be of any desired curve or angle, and there may be one or more grooves between each couple of slits.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-- A screen-plate for paper-machines having its upper face longitudinally grooved or other wise depressed between the slits, substantially as and for the purposeset forth.

JAMES M. SHEW.

Witnesses:

J NO. B. BROWN, JOEL HoUsTEN. 

